This proposal is to study the incidence and mechanisms of allergic reactions to natural rubber. Rubber allergy has been well-described in case reports over the past 10 years; life-threatening reactions have been documented. This phenomenon appears to be IgE-mediated, and preliminary evidence strongly suggests that the antigen is a protein. Recent studies of children with spina bifida suggest that these patients may forma a high- risk group. Health care workers have also been mentioned as a high-risk group, and the increased use of natural rubber gloves in the health care industry in recent years may increase the occurrence of this phenomenon. (1) A prospective case-control serologic study to assess the risk of rubber allergy in children with spina bifida (currently in progress) will be continued and expanded to other possible risk groups. Rubber-specific IgE will be sought using a radioallergosorbent test. The antibody immune response to rubber in these patients (or, at least, in the patients already shown to have IgE-mediated rubber reactions) will be further characterized, using immunoblotting techniques. (2) The isolation and biochemical characterization of rubber antigen(s) will be done as follows. IgG will be purified from a patient known to have rubber-specific IgG, or from rabbits immunized with eluted immunoreactive protein bands. This IgG will then be used to affinity- purify the antigen(s). Antigenicity will be tested in the basophil histamine release system; purity will be assessed by 2D electrophoresis and N-terminal analysis. The antigen(s) will then be analyzed for amino acid and carbohydrate content and, if indicated, amino acid sequencing will be done. (3) A competitive or sandwich radioimmunoassay for rubber antigen(s) will be developed, using the rabbit antisera and purified (or partially purified) antigen derived in step 2. Such an assay will be useful both for allergen avoidance in rubber-sensitive individuals and for the assessment of manufacturing techniques to minimize the presence of antigen in rubber. (4) Rubber products will be screened for the presence of antigen.